Speed control and steering mechanism



Jan. 14, 1941.

R. F. HAGGERTY SPEED CONTROL AND STEERING MECHANISM Filed Jan. 6, 1959 Inventor Rub er't ,fil'lagg'erty Attmrne Patented Jan. 14, 1941 UNITED STATES PATENT OFFICE Robert F. Haggerty, United States Army, Aberdeen, Md.

Application January 6, 1939, Serial No. 249,615

4 Claims.

(Granted under the act of March 3, 1883, as

amended April 30,

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to a speed control and steering mechanism and is particularly applicable to hydraulic variable speed gear devices in which the direction and speed of the driven shaft of an hydraulic motor is regulated by movement of a tilting box associated with a pump operated by the driving power.

The purpose of this invention is to provide a mechanism for operating a pair of power controls such as the tilting boxes of a pair of hydiraulic variable speed gear devices whereby the driven members may be operated in unison or may be varied to accomplish steering. As an example the driven members may be the tracks of a tracklaying vehicle in which steering is performed by driving the tracks at different speeds or in opposite directions.

A further object of the invention is to so arrange the mechanism that the speed control and the steering units have elements in common.

To these and other ends, the invention consists in the construction, arrangement and combination of elements described hereinafter and pointed out in the claims forming a part of this specification.

A practical embodiment of the invention is illustrated in the accompanying drawing, wherein:

Fig. 1 is a plan view of a mechanism constructed in accordance with the invention;

Fig. 2 is a sectional View on the line 22 of Fig. 1 with parts in elevation;

Fig. 3 is a perspective view of the tilting box control shaft.

Referring to the drawing by characters of reference there is shown a pair of tilting boxes A and B each belonging to the pump unit of an hydraulic variable speed gear of the Waterbury type and arranged to be tilted to regulate the direction and speed of a driven member by means of the respective control shafts C and D. The worms on the control shafts are oppositely threaded so that rotation of the control shafts in opposite directions causes the two tilting boxes to move in the same direction.

A pinion 5 on the shaft C meshes with a rack 6 and a pinion I on the shaft D meshes with a rack 8. The racks are each mounted on one of a pair of rods 99 slidably carried in a pair of supports I and II.

An axially movable rod I2 positioned between the racks 6 and 8 has one end mounted in the support I0 while its other end passes through a sleeve I3 extending through the support II. The sleeve is provided externally with splines I4 whereby it is slidably and rotatably in engagement with a gear I5 whose hub I6 is rotatably mounted in the support II. The hub I6 includes a provision in the form of a ring or flange I! which engages the support on the side opposite to the gear and thereby holds the gear against axial displacement.

A bevel gear I8 on one end of the sleeve I3 abuts against a shoulder I9 on the rod I2 and meshes with a bevel gear 20 which is formed on a pinion 2| that is mounted on a pin 22 carried by the rod I2. The pinion 2I is positioned between and meshes with the racks 6 and 8.

A plug 23 threaded in one end-of the rod I2 confines the sleeve I3 and includes an eye 24 for attachment of a link 25 that is reciprocated by means of a control shaft 26 and a hand lever 21.

A gear 28 meshing with the gear I5 is fixed on a shaft 29 which carries a pinion 30 driven in opposite directions by a gear 3| under control of a rudder bar 32.

The speed control of the driven members is accomplished by operating the hand lever 21 to move the rod I2 and sleeve I3 axially and displace the racks 6 and 8 equal amounts in the same direction. The control shafts C and D are thereby rotated in opposite directions but since they are oppositely threaded the associated tilting boxes A and B will be moved in the same direction.

The steering control of the driven members is accomplished by operating the rudder bar 32 to rotate the shaft 29 and also the sleeve I3 irrespective of its longitudinal displacement under influence of the hand lever 21. Rotation of the sleeve I3 in either direction drives the pinion 2| and displaces the racks B and 8 equal amounts As a consequence the I or in different directions will provide for steering of the vehicle.

I claim:

1. Actuating means for a pair of hydraulic variable speed gear devices each including a tilting box with a rotatable control shaft, the shafts being oppositely threaded, a pinion on each shaft, a pair of axially movable racks each meshing with one of the lpinions, an axially movable rod between the racks, a pinion carried by the rod and meshing with both racks, a bevel gear on the pinion, a sleeve rotatable on the rod and movable axially therewith, a bevel gear on the sleeve meshing with the bevel gear on the pinion, arotatably and axial immovably mounted gear splined on the sleeve, means for rotating 'said gear to rotate the sleeve and the pinion. on the rod to displace the racks equal amounts in opposite directions, and means for moving the rod and sleeve axially to displace the racks equal amounts in the same direction.

2. Actuating means for a pair of hydraulic variable speed gear devices each including a tilting box, a pair of axially movable racks each con trolling the tilting movement of a tilting box, an axially movable rod between the racks, a pinion carried by the rod and meshing with both racks, a sleeve rotatable on the rod and movable axially therewith, gearing between the sleeve and pinion,

a rotatably and axially immovably mounted gear splined on the sleeve, means for rotating said gear to rotate the sleeve and the pinion on the rod to displace the racks equal amounts in opposite directions, and means for moving the rod and sleeve axially to displace the racks equal amounts in the same direction.

3. Actuating means for a pair of hydraulic variable speed gear devices each including a tilting box, a pair of axially movable racks each controlling the tilting movement of a tilting box, an axially movable rod between the racks, a pinion carried by the rod and meshing with both racks, a sleeve rotatable on the rod and movable axially therewith, gearing between the sleeve and pinion, means for rotating the sleeve to drive the pinion on the rod and displace the racks equal amounts in opposite directions, and means for moving the rod and sleeve axially to displace the racks equal amounts in the same direction.

4. Actuating means for a pair of power controls, a pair of axially movable racks each regulating the movement of a control, a pinion meshing with both racks, means for rotating the pinion to displace the racks equal amounts in opposite directions, and means for bodily moving the pinion to displace the racks equal amounts in the same direction.

ROBERT F. HAGGERTY. 

